This invention relates to a multiple channel (particularly a two channel) microcomputer-based pressure recorder having internal pressure transducers that are intrinsically transportable with the recorder. The pressure recorder, specifically adapted for portable use at the surface of an oil or gas well, also has an internally stored data base which includes calibration factors that enable automatic correction of transducer-responsive signals into signals representing the correct magnitudes of sensed pressures.
Highly accurate quartz pressure transducers have been used in memory recorders lowered into oil or gas wells to sense pressures down in the wells and to provide electrical signals representative of the sensed pressures. Such signals have been stored downhole or transmitted to the surface for storage or display. These devices typically are not adapted for use at the surface of a well outside the well bore.
Although there are devices that can be used at the surface of such wells to record pressure, those that we are aware of typically have only one internal pressure sensor and/or do not provide outputs that are automatically corrected with calibration factors and locally displayed through integral real-time displays.
In view of the foregoing, there is the need for a pressure recorder specifically adapted for use at the surface of an oil or gas well that automatically provides corrected pressure values without requiring operator intervention. There is also the need for such a device to be able to simultaneously monitor at least two pressures with internal pressure transducers. For example, both tubing pressure and annulus pressure sometimes need to be monitored at the wellhead. These pressures cannot be monitored at the same time with a device that can be connected to only one pressure source at a time. There is the further need for a pressure recorder that has multiple highly accurate quartz pressure transducers as integral parts so that they are transportable with the recorder as a single self-contained unit. Such a pressure recorder should also be capable of locally displaying the corrected pressure values in real time and of transmitting the data in real time to a remote location.